hmm..just wondering. normally i always drive around with the windows open. i do this because the weather is always great in san diego and i thought came to me. i save gas by not using the air conditioner. But how much exactly am i saving? is it a significant amount?

 

Believe it or not, most newer cars get better highway mileage with the A/C on.. This is because your driving with the windows up making for better aerodynamics.. City driving with the windows down should really make little difference..

Steve (k2we) Dobbs Ferry, NY 12,146 miles since Sept 17th...

 

You will use more fuel with your windows down due to the aero drag...But You will use even more fuel with the A/C on due to the energy required to run the compressor....I heard 5% for windows down and like 10-15% for the AC...anyone know if that's true???

 

Driving on the highway with windows up and A/C on will use less fuel than with windowns down and A/C off.

 

This is true. This is of course on the highway. If you are cruising around at much slower speeds, then like k2we said, probably makes little difference.